With　the　aid　of　a　electro-opto-thermal　model　of　a　two-dimensional　(2-D)　vertical-cavity　surface-emitting　laser　(VCSEL)　array,　the　thermal　characteristics　of　a　4x4　VCSEL　array　is　simulated.　It　is　shown　that　there　is　a　higher　temperature　in　the　central　region　of　the　device,　which　limits　the　optical　output　performance.　In　order　to　enhance　the　optical　output　power,　a　novel　VCSEL　array　with　non-uniform　oxidation　aperture　is　designed.　As　a　result,　the　peak　junction　temperature　is　decreased,　and　the　non-uniformity　of　junction　temperature　and　bias　current　density　among　array　cells　are　improved　obviously.　Furthermore,　experimental　results　demonstrate　that　the　optical　output　power　of　the　novel　VCSEL　array　is　increased　from　33.5mW　to　38.6mW　with　an　improvement　of　15.22%　and　a　superior　far-field　light　spot,　when　compared　with　the　uniform　device.　The　non-uniform　oxidation　aperture　design　sheds　light　on　a　effective　method　to　enhances　the　thermal　behaviour　and　optical　performance　of　VCSEL　arrays.